Alarm clock movement



Jan. 11, 1944. H, JUNGHANS 2,338,944

ALARM CLOCK MOVEMENT Filed ON 14, 1940 Jnren/ar:

Hahn/1f 1717155311;

resistance is usually so great Patented Jan. 11, 1944 ALARM CLOCKMOVEMENT Helmut Junghans, Schramberg-Sulgen, Eckenhof, Germany; vestedin the Alien Property Custodian Application October 14, 1940, Serial No.361,148 In Germany August 30, 1939 2 Claims.

This invention relates to an alarm clock moveinent, and has for itsobject to prevent return motion of the alarm setting spindle.

In the known alarm clock works in which the alarm locking or clickspring is controlled by a .member attached to the alarm setting wheeland having a notch cooperating with a. catch, the alarm setting spindlemust be rotated in one directiOn only so as to insure relativedisplacement of the attached member and the catch in the same direction.If the spindle is turned in opposite direction, the catch strikes theinclined edge of the notch in the attached member and during furtherrotation the clock movement is driven backward by the intermediategears. Due to the earing up in the clock movements, the frictional thatth alarm setting means will break. I

Various proposals have been made to prevent return motion of. the alarmsetting spindle in a positive manner, and one of them provides forinstance a screw-on setting knob which will unscrew from the end of thesetting spindle when an attempt is made to turn the latter in the wrongdirection. This arrangement is, however, open to the objection that theknob is often lost and two kinds of knobs and fastening means arerequired for the alarm setting and the minute spindies.

It has further been suggested to interpose clutch couplings between thealarm setting spindle and the toothed wheel supporting the attachedmember mentioned, but the practical application of this suggestion wasfound to require too many additional structural elements.

According to the invention, the difliculties are eliminated byconnecting the alarm setting spindle with a fixed point of the clockthrough the medium of a Schwarz coupling spring which is of the volutetype and so wound upon a plain shaft as to hug it with a certain initialtension. One end of this spring has a tangential continuation which isengaged by an alarm shut off lever,

and the other end thereof is anchored at the fixed 45 point on the frameof the mechanism close to the shaft. Notwithstanding its smalldimensions in the present instance, a coupling spring of this type iscapable of transmitting relatively great forces and of offering so greata resistance to any attempt to turn th alarm setting spindle in thewrong direction that instant and effectively at tention is called tothis faulty manipulation without injuring the clock.

The use of such a coupling spring for the alarm setting spindle afiordsthe advantage that the alarm setting knob like the hand setting knob canbe secured to its spindle by means of a square end thereon and that bothknobs can be made 5 alike and interchangeable. In clocks provided withthe widely used shut off members which upon winding the alarm drivingspring are disengaged from the alarm escapement wheel by a restoringspring, the Schwarz coupling spring on 10 the alarm setting spindle mayserve also for another purpose. Instead of cutting off one end thereofas mentioned, it is allowed to stand out from the spindle and to actthus as restoring spring for the alarm stop. The coupling spring ispreferably initially tensioned when installed between the alarm stop andthefixed point of the clock.

One form of the invention is illustrated by way of example in. theaccompanying drawing, in 20 which Figure 1 is a front view of alarmsetting and stopping parts according to the invention; and

Fig. 2 is a top view thereof.

a is the alarm setting spindle, b the hand set ting spindle, 01 is thefront plate and 02 the rear plate, in which plates the two spindles andthe other parts of the clockwork are arranged. d is the dial, and cdesignates the back wall of the casing. On the alarm setting spindle a apinion is disposed which engages the alarm setting wheel a having anattachment g1. h is a toothed wheel which is rotated once every 12 hoursthrough intermediate gears, not shown, and which is firmly connectedwith the hour-hand i. The Wheel h at cooperates in known manner with thealarm looking spring is and also with the attached member g1 through thenose or catch hi. From the alarm escapement wheel I the hammer rod m isdriven in the usual way. m1 is the stop arm cooperating all with thelocking spring is, and m2 is the hammer.

The stop lever n is freely and oscillatably disposed on the spindle awith the aid of two perforated flaps n1 whose distance apart correspondsto the width of the frame. Through its arm m it can engage theescapement wheel I in known manner, and its arm n3 is engaged by theshut ofl? knob o.

A Schwarz coupling spring 12 is closely Wound upon the alarm settingspindle a with initial tension. One end of the spring, designated in,engages a hole on of the front plate 01 so as to effeet a couplingbetween the spindle a and a fixed point of the clock. The other end 712of the spring 1) lies on a continuation m of the stop lever 12. 55 Thespring p is arranged with initial tension between the plat 01 and thestop lever n in such manner that the lever n is subjected to springpressure which urges it into releasing position. Both setting spindles aand b are provided with square ends :11, In of the same dimension towhich similar setting knobs q, r are attached. The coupling spring p isbuilt in so that the spindle a can be turned only in the direction ofthe arrow s, Fig. 1.

The alarm setting shaft a is turned by the knob q until the alarm handt, which is fast with the gear wheel g in mesh with the pinion f,isatthe desired setting on the alarm dial. This rotation of the shaft ais counterclockwise. If it be attempted to rotate the shaft'a clockwise,the coils of the spring 10, owing to frictional engagement of the shafttherewith, will be causedlto wrap more firmly about the shaft and oppose;s-uch clockwise rotation thereof in a manner preventing damage to themechanism.

The alarm isreleased as follows. .In the run ning of the clockwork, th-minute hand shaft 2.

through gearing notshown, is rotated. The wheel h with thelug hi isvifast on this ,shaftb. The alarm stop spring k pressesth lug hi:againstthe attachment or on the alarmsetting wheel which attachment orhas a notch, not shown, the position of which depends on thesetting ofthe alarm hand. The shaft b. can move axially to .a certain extent inthe frame plates 01, .02. Whenthe wheel h with vthelug hi hasrotateduntilthe. latter is opposite the said, notch in theattachmentgltlie lug ,hl by the action of the spring k and axial movement of shaftb ,engagesthe notch. This resultsin the oifset end of ,thevvsmfing' Itbeing pushedtowar-ds the dial d (Fig. 2), releasing the hammer arm m1,whereby the wheel I can rock the alarm hammer 7m to and fro.

To shut voff the alarm, the shut off knob o .is pressed inwards anditsconical point forces .the ,stop lever arm m upwards against the actionofthe spring end 102, and the point nz oi the lever n enters a tooth gapof the escapement wheel Z. The next tooth of this wheel now holds thelever 12 in known manner, and in engagement with the Wheel teeth, sincethe full strength of the alarm spring is operative thereon. Uponremoving the finger from the knob o the latter returns to normalposition asshown'in' Fig. 2.

The return of the stop lever n to initial posil tion is eifected inknown manner merely by winding the alarm spring. This releases thepressure {of the-escapement wheel I on the point 112 of the lever nenabling the latter under the action of the spring end 102 to return incounter-clockwise di- *15 'recti'onto release position.

What is claimed is:

l...Alarm clock mechanism comprising a frame, alarm release settingmeans including a member intended for rotation in one direction only, an

'20 alarmhand setting stem rotatably mounted in said frame and-operatively connected to said membena coil spring tensionedaround aidstem and frictionally engaging the same said spring having one of itstends fixed to said frame and being arranged to be de-tensioned to freesaid stem when the ,latter .is rotated in the proper alarm hand settingdirection but .to be tightened around and lock said stem when the latteris turned in the wrong direction, a tangentially extending portion atthe other end of said coil spring,,an alarm winding spring, and an alarmshut off lever held in alarm shutbffposition by the action of saidwinding spring and released upon winding up said winding spring, saidshut 5 01f lever being urged into release position by said tangentiallyextending spring portion.

I 2. Alarm clock mechanism according to cl'a'iml in which the alarm shutoff lever is pivotableon the alarm hand setting stem.

